package io.rong.imkit.picture.decoration;

import android.graphics.Rect;
import android.view.View;
import androidx.recyclerview.widget.RecyclerView;

public class GridSpacingItemNotBothDecoration extends RecyclerView.ItemDecoration {

    private int spanCount;
    private int spacing;
    private boolean includeEdge;
    private boolean isRemoveBoth;

    public GridSpacingItemNotBothDecoration(
            int spanCount, int spacing, boolean includeEdge, boolean isRemoveBoth) {
        this.spanCount = spanCount;
        this.spacing = spacing;
        this.includeEdge = includeEdge;
        this.isRemoveBoth = isRemoveBoth;
    }

    @Override
    public void getItemOffsets(
            Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        int position = parent.getChildAdapterPosition(view); // item position
        int column = position % spanCount; // item column
        if (includeEdge) {
            if (isRemoveBoth) {
                // 去掉两边的spacing
                outRect.left =
                        column == 0
                                ? 0
                                : spacing
                                        - column * spacing
                                                / spanCount; // spacing - column * ((1f / spanCount)
                // * spacing)
                outRect.right =
                        column == spanCount - 1
                                ? 0
                                : (column + 1)
                                        * spacing
                                        / spanCount; // (column + 1) * ((1f / spanCount) * spacing)
            } else {
                outRect.left =
                        spacing
                                - column * spacing
                                        / spanCount; // spacing - column * ((1f / spanCount) *
                // spacing)
                outRect.right =
                        (column + 1)
                                * spacing
                                / spanCount; // (column + 1) * ((1f / spanCount) * spacing)
            }
            if (position < spanCount) { // top edge
                outRect.top = spacing;
            }
            outRect.bottom = spacing; // item bottom
        } else {
            outRect.left = column * spacing / spanCount; // column * ((1f / spanCount) * spacing)
            outRect.right =
                    spacing
                            - (column + 1)
                                    * spacing
                                    / spanCount; // spacing - (column + 1) * ((1f /    spanCount) *
            // spacing)
            if (position >= spanCount) {
                outRect.top = spacing; // item top
            }
        }
    }
}
